My professional focus includes various research questions related to hydrology and biochemistry, from catchment headwaters to coastal groundwater.
Coastal hydro-biogeochemistry
Coastal wetlands are the interface between uplands and the ocean, intercepting, transforming, and transporting pollutants on their course to the marine environment and removing and storing a large amount of carbon. To date, coastal wetland research has focused on ocean forcings as the principal modulator of biogeochemical cyclings and the principal threat to marsh sustainability. Coastal wetlands are hydrologically connected to regional groundwater environments through their upland and subsurface boundaries, and thus, regional groundwater conditions may also mediate coastal wetland ecosystem processes. Given that terrestrial groundwater systems are under siege due to climate change-induced droughts and anthropogenic influences, understanding how upland watersheds influence coastal wetland health, function, and biogeochemical cycling is critical. I seek to close this critical knowledge gap by investigating regional groundwater effects on coastal wetland hydrology, porewater biogeochemistry, and greenhouse gas fluxes.
For more details, check out these papers:
Guimond J, Grande E, Michael H, Pratt D, Herndon E, Noyce GL, Ward N, Forbrich I, Regier P, Berens M, et al. 2025. The hidden influence of terrestrial groundwater on salt marsh function and resilience. Nature Water 3: 157–166 DOI: https://doi.org/10.1038/s44221-024-00384-6
Montalvo MS, Grande E, Braswell AE, Visser A, Arora B, Seybold EC, Tatariw C, Haskins JC, Endris CA, Gerbl F, et al. 2024. A Fresh Take: Seasonal Changes in Terrestrial Freshwater Inputs Impact Salt Marsh Hydrology and Vegetation Dynamics. Estuaries and Coasts DOI: 10.1007/s12237-024-01392-1
Grande E, Seybold EC, Tatariw C, Visser A, Braswell A, Arora B, Birgand F, Haskins J, Zimmer M. 2023a. Seasonal and Tidal Variations in Hydrologic Inputs Drive Salt Marsh Porewater Nitrate Dynamics. Hydrological Processes 37 (8): 1–17 DOI: 10.1002/hyp.14951
Grande E, Visser A, Oerter E, Arora B, Seybold EC, Tatariw C, Braswell A, Montalvo M, Zimmer M. 2023b. Flow Directions and Ages of Subsurface Water in a Salt Marsh System Constrained by Isotope Tracing. Estuaries and Coasts DOI: 10.1007/s12237-023-01237-3
Grande E, Arora B, Visser A, Montalvo M, Braswell A, Seybold E, Tatariw C, Beheshti K, Zimmer M. 2022. Tidal frequencies and quasiperiodic subsurface water level variations dominate redox dynamics in a salt marsh system. Hydrological Processes 36 (5): 1–16 DOI: 10.1002/hyp.14587
Surface water-groundwater exchanges and storage dynamics
Streamflow generation and water storage are well-studied aspects of watershed hydrology. However, we still lack information about how these processes contribute to stream-aquifer interactions and biogeochemical processes. I use isotopic and hydrological methods to examine the major mechanisms for streamflow generation across climatic settings. For more information, check out these papers:
Lerback J, Bibby R, Danielsen J, Garguilo M, Grande E, Harm AJ, Minn K, Moran J, Oerter E, Visser A. 2024. How Rains and Floods Become Groundwater: Understanding Recharge Pathways With Stable and Cosmogenic Isotopes. Hydrological Processes 38 (12): e70020 DOI: 10.1002/hyp.70020
Grande E, Zimmer MA, Mallard JM. 2022. Storage variability controls seasonal runoff generation in catchments at the threshold between energy and water limitation. Hydrological Processes 36 (10): e14697 DOI: 10.1002/hyp.14697
Grande E, Moran JE. 2021. Patterns in Radon Activity in California Groundwater. ACS ES&T Water: 1–16 DOI: 10.1021/acsestwater.1c00226
Grande E, Visser A, Moran JE. 2020. Catchment storage and residence time in a periodically irrigated watershed. Hydrological Processes 34 (14): 1–17 DOI: 10.1002/hyp.13798
Grande E, Visser A, Beitz P, Moran J. 2019. Examination of Nutrient Sources and Transport in a Catchment with an Audubon Certified Golf Course. Water 11 (9): 1923 DOI: 10.3390/w11091923
Streamflow generation in mountainous systems
We are addressing hydrological problems associated with climate change, which is expected to cause a low-to-no snow future for California in as little as 35 years. These stressors on the terrestrial water cycle are felt most keenly in mountainous regions where comparatively little water management occurs. For example, in California, ~75% of the freshwater originates in the northern, mountainous part of the state. However, we know little about how drought and climate change affect these crucial waters. My lab has teamed up with CalTrout to define and quantify source areas and flows, assess ecosystem sensitivity to climate change, and determine how these systems support wild cold-water fish.
